The T-even bacteriophage-E. coli system is being investigated as a model system of viral invasion, viral structure and viral assembly. It has been found that polyglutamate derivatives of folic acid play a critical role in joining viral tail fibers to the phage baseplate. It is proposed to investigate the exact chemical mechanism of tail fiber attachment using antibodies directed against the polyglutamate portion of the folate compound. In addition it has been found that phage baseplates contain 6 atoms of zinc. Current work is directed to determining which viral gene is responsible for inducing the formation of a zinc protein. BIBLIOGRAPHIC REFERENCES: Bacteriophage T4 Baseplate Components II. Binding and Location of Bacteriophage-induced Dihydrofolate Reductase. Lloyd M. Kozloff, Louise K. Crosby, Murl Lute, and Dwight H. Hall, J. Virol. 16:1401-1408, 1975. Bacteriophage T4 Baseplate Components III. Location and Properties of the Bacteriophage Structural Thymidylate Synthetase. Lloyd M. Kozloff, Louise K. Crosby, and Murl Lute, J. Virol. 16:1409-1419, 1975.